Electric water heater



A. C. HULBERT. Y

ELECTRIC WATER HEATER.

APPLICATION HLEDIUNE lil, 192|. 1,427,596.

Patented Aug. 29, 1922.

01H u bert l To all 'w m t may concern f .Be it known that I. ANsEL C.

msm. c. Hummm, or sm raANcisco, oamronma.

ELECTBIG- WATER HEATER.

Application :Iliad June 11,

Hiimnn'r, a'citizen of the United States, residing at San Francisco, in the county of certain new anduseful Improvements in Electric lVater Heaters, of whichthe following is a specification. v

This invention relates to electric heating devices, and is 'especially designed for `.use in heating water.

One of the objects of my'invention is, to obtain a greater heating surface than has been attained in prior devices, without materially increasing the space occupied by' the heater.

A further purpose of this invention is, to encase the heating element in a continuous Ametal tube which is returned upon itself, so that the ends may be sealed into a single Irgl the following description, 'I shall refer to the illustrations in the accompanying drawing, in which :-d

Figure l I is a perspective View of the complete heater showing the devicev in positionin a reservoir connected to a water pipe.

Figure 2 isa perspective view, partly broken away, of the upper part of the heating element and its enclosing tube.

Figure 3 is a perspective view of the heating element with its cover or tube partly torn off, and certain insulating elements bent away from `the core.

Figure 4 is an enlarged detail longltudinal section through the central -part of the heating element and its cover ,or tube.

' or may not have Figure 5 isa section on the line 5-5 of' Figure 4.

Fig. 6 is a up er portion of the heater.

n the embodiment of the invention shown in the accompanying drawings, there is pro-` vided, a heating element `having a core 10 which consists of a flat strip of asbestos or other like insulating material whlch may its edges notched, 0r serrated to receive the wire. Around each end of this strip 1s woundresistance wire 11, the wire on the end being wound i n one direction, as right handed, while the w 1re o n the other end is wound in theopposlte d1- rection or left handedl. In ordert accomplish this -winding and old the central ortion of the .winding tightly in place, without bringing too great l speciacaaon of Letters raient.

San Fran-A cisco and State of California, have invented ends lof binding plate 21 and held vertical sectional view of theat the same timeratentea Aug. 29, 1922,'

1921. Serial No. 476,783.

strain thereon, when the heating element is bent to complete the heater, the center ofv the core 10 is notched as at 12 on the side which eventually forms the inside of the bend. an opening 13, and the ends of the wire are run through respective openings, so as to leave a central portion 14 connecting the.

coils. At each end of the core', there is also provided an opening 15 through which the respective wire end is threaded, In order to hold the convolutions of the coils apart, an insulating strand 18 is wound around the core between said convolutions. v

Extending longitudinally ofthe core and covering the resistance wire and insulating strand, lis a pair ofrchannel shaped insu1at strips17 preferably formed of mica or ing other like heat resisting insulatingl material.

The respective' wire ends are soldered, .or

otherwise permanently secured to terminals 18 and the entire element, with the exception of these terminals is covered by 'a metallic protecting tube or cover 19 fitting closely over the channel shaped strips.

After the heating elementl ls assembled in this manner, thetube and contained element are -doubled at 'they center with the notch 12 inward, so asto vform a narrow U-sha`ped structure',' and1the' ends are then firmly soldered or brazed kto a hollow plug 20 with the terminals 18 rojecting up' therethrough. These termina an insulating plate 21 and have the lower posts 22 connected thereto. .A second insulating plate 23 is fitted on the tothe plug by screws '24; The binding posts pro]ect through this plate 23 and carry the usual knurled nuts 25.

It is obvious material principles of the invention.

having its ends soldered or brazed to said" plug, and a' helically coiled resistance wire extending through said tube, and having its ends joined to said terminal connectors.

2. An ing a core of heat. resisting insulating material, a resistance wire wound on said core in spaced convolutions, a plurality vvof trough run through that various changes may be `made 1n the f orm and construction offthe apparatus, wlthout departing from `1 .the

having electrical heating element includ.

l Spaced at each side of this notch, is

Having thus described vthe invention, 1.00

shaped insulating strips extending longitu- V' dinally of the core and fitting closely on the wire windings, and a tube fitting closely on the strips, and thereof to hold said strips in position and protect the insulation, the windings and the core.

3. Ail electrical heating element including a core of heat resisting insulating material, a resistance wire wound on said core in spaced convolutions, insulating strips covering said wire windings, and a protective tube fitting over said insulating strips and completely covering the same, said tube and the parts therein being medially bent to produce a U-shaped structure having closely arranged legs.

4. An electrical heating element including a core of heat resisting insulating material, a resistance wire wound on said core in spaced convolutions, a. plurality of trough shaped insulating strips extending longitudinally of the core and fitting closely on the wire windings` and a tube fitting closely on the strips, and extending from end to end thereof to hold said strips in position and protect the insulation, the windings and the core, said tube and the parts thereinbeingv medially bentto provide a U-shapedstructure having closely arranged legs.

5. An electrical heating element including a core of heat resisting insulating material, a resistance wire wound on said core in spaced convolutions, insulating strips covering said wire windings, a protective tube fitting over said insulating strips and completely covering the same. said tube and the parts therein being medially bent to provide a U-shaped structure having closely arranged legs. al plug having said legs fixed thereto, and Wire connection devices carried by andinsulated from the plug, one of said devices being connected electrically to one extending from end to endv of the ends of the resistance wire and the other of said devices being connected to the other end of said resistance wire.

6. 'An electrical heating element including a core of heat resisting iiysulating material, a resistance wire wound-on said core in spaced convolutions, a plurality of trough shaped insulating strips extending longitudinally of the core and fitting closely on the wire windings, a tube fitting closely on the strips and extending from end to end thereof to hold said strips in position andI protect the insulation, the windings and the core, said tube and the parts therein being medi- .ally bent to provide a U-shaped structure having closely arranged legs, a plug having said legs fixed thereto. and wire connection devices carried by and insulated from the plug, one of said devices being connected electrically to one of the ends of the resistancewire and the other of said devices being connected to the other end of said resistance wire.

7. That method of forming an electrical heater which consists in Winding a resistance wire on a flexible insulating core, covering the core and wire with insulating strips, inserting the covered core and Wire in a closely fitting tube, and bendingthe assembled article at its middle to form a U- shaped structure.

8. That method of forming an electrical heater which consists in winding a resistance wire on an insulating core, covering the core and wire 'with insulating strips, inserting the covered core and Wire in a closely fitting tube. bending the assembled article at its middle to form a U-shaped structure, and connecting the extremities of said tube fixedly to a plug, y

In testimony whereof I affix my signature.

ANSELv C. HULBERT. 

